Types of Thermometers and How to Accurately Measure Temperature
We all have been there when we are not feeling like going to school due to the homework which we haven’t done. We try everything possible to make our parents believe that we have a fever and there is nothing we are going to miss today. Then our farther brings up the ultimate testing weapon, the thermometer, and all our dreams of having a rest day from school went up in smoke. Today we are going to talk about the technology behind thermometer and how one needs to read the thermometer correctly.
What Is The Correct Reading Of The Thermometer?
Before we look at how to read a thermometer, lets first see how thermometer finds out the body temperature. On which mechanism does it work and what makes it provide us with accurate body temperature. In most of the cases, we see thermometer using Mercury as a liquid to measure the temperature. The thermometer is made from a glass tube that is sealed from both ends so that no fluid can escape it. When the temperature around the glass tube increases, the liquid starts to expand in the tube. As a result, we see the liquid go up and reach the higher units of temperature.
The glass tube has a backboard inside in which the unit to measure temperature is marked. In everyday thermometer reading temperature, we have Fahrenheit unit of measurement. We measure the temperature by checking the level of the liquid on the backboard, which has degrees written on it.
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Furthermore, Alcohol is also used in lots of thermometers as it remains in liquid form in most of the temperature that we have on earth. It is easy to find an alcohol-based thermometer in school with the colour red or green to show us the temperature. On the other hand, Alcohol is not used when it comes to measuring high temperature as it starts to boils at 80 degrees Celsius. So in these cases, industries use Mercury as the base for thermometer liquid.
Types of Thermometer
There are several ways to check the body temperature of an individual with the advancement in technology. Scientists and doctors have created a wide variety of thermometer which can be used to measure the body temperature. Given below is the list of different types of thermometer.
Digital Thermometer
This is not the latest thermometer that has been developed. But it is the most accurate one among all the temperature measuring thermometers out there in the market. Just like an old school thermometer you need to insert it in your mouth and put it under your tongue to measure the temperature.
Or you can put it under your arm to measure the temperature. You can find them in your local drug store, and they can be used both in the public and private environments.
Forehead Thermometers
These are the latest thermometers that we see today, and they are pretty convenient as you don’t even have to get in contact with the patient. As a result, it is not as accurate as of the first one on our list. They read the heat signal using infrared technology.
Plastic Strip Thermometers
If you want to know if the patient has a fever or not, you can use this thermometer. It’s more of the test then a thermometer, but still, a lot of doctors considered it to be one. You won’t be getting an exact temperature reading from this machine. It merely provides you with an indication of whether the person has a fever or not. To use it, all you need to do is put the strip on the forehead of the patient, and if the color changes to danger, the person might have a fever.
Pacifier Thermometer
These are used in case of babies that are older than 3 months, and this thermometer requires a couple of minutes to provide you with an accurate reading.
Glass And Mercury Thermometer
Our last pick is glass and Mercury, this is the old combination, and it works like a charm, this thermometer configuration gives you the most accurate reading of the temperature. You need to place it inside your mouth, or you can put it in your armpit to measure the temperature.
How To Measure Body Temperature By Thermometer?
Given below are the step that you need to follow to measure temperature from thermometer reading
First, wash your hands with soap and water. In addition to this, clean your thermometer sensor with rubbing alcohol and then rinse it.
Before taking the temperature, do not eat or drink for about 5 minutes at least.
Now place the sensor of your thermometer under your tongue.
Please keep it in the same position for roughly 50 seconds.
If you have a digital thermometer, it will make a beeping noise once the reading is complete.
Otherwise, you can take it out after 50 seconds and note down the reading of liquid alongside the degrees.
FAQs on Thermometer Reading Temperature Explained
1. What is the basic principle behind how a thermometer measures temperature?
A thermometer works on the principle of thermal expansion. The substance inside the thermometer, such as coloured alcohol in a lab thermometer or a sensor in a digital one, expands when it gets hotter and contracts when it gets cooler. This physical change is precisely calibrated against a temperature scale (like Celsius or Fahrenheit) to provide an accurate reading.
2. What is the main difference between a clinical thermometer and a laboratory thermometer?
The main differences relate to their purpose, range, and design:
- Purpose: A clinical thermometer is specifically designed to measure human body temperature, while a laboratory thermometer is used for scientific experiments to measure the temperature of various substances.
- Temperature Range: A clinical thermometer has a narrow range, typically from 35°C to 42°C (95°F to 108°F). A laboratory thermometer has a much wider range, for example, from -10°C to 110°C.
- Design: A clinical mercury thermometer has a small bend or constriction (kink) in the tube just above the bulb. This prevents the mercury from falling back down immediately, allowing time to read the temperature accurately. Laboratory thermometers do not have this kink.
3. How do you correctly read a clinical thermometer to get an accurate temperature?
To read a clinical thermometer correctly, follow these steps:
- First, ensure the thermometer is clean.
- If using a mercury thermometer, jerk it a few times to bring the mercury level below 35°C.
- Place the bulb of the thermometer under your tongue for about one minute.
- Remove the thermometer and hold it horizontally at eye level.
- Rotate it slowly until you can see the reading where the liquid column ends on the scale. For a digital thermometer, simply read the numbers on the display after it beeps.
4. Why must a thermometer be kept under the tongue for an accurate body temperature reading?
The area under the tongue is a closed cavity with a rich supply of blood vessels close to the surface. This location, known as the sublingual pocket, provides a stable reading that accurately reflects the body's core temperature. Placing it in other locations, like the armpit, can be influenced by the surrounding air, often resulting in a lower and less precise reading.
5. What is considered a normal body temperature, and at what reading does it indicate a fever?
A normal human body temperature is generally accepted to be around 37°C (98.6°F). However, this can vary slightly from person to person. A temperature reading of 38°C (100.4°F) or higher is typically considered a fever, indicating that the body is fighting an infection or illness.
6. How does reading a modern digital thermometer differ from an older mercury thermometer?
Reading a digital thermometer is straightforward; you turn it on, place it, and wait for a beep, after which the temperature is clearly displayed on an LCD screen. In contrast, reading a mercury thermometer requires more skill. You must hold it at eye level and carefully locate the end of the thin, silver mercury line against the calibrated glass markings, which can be difficult to see. Additionally, mercury thermometers must be manually reset by shaking, a step not required for digital models.
7. Why are mercury thermometers now considered unsafe and largely replaced by digital ones?
Mercury thermometers are unsafe because they are made of glass and can break, releasing mercury. Mercury is a highly toxic heavy metal. If the vapour is inhaled or the liquid is touched or ingested, it can cause severe health issues, affecting the nervous system, kidneys, and brain. Digital thermometers are much safer as they are more durable and contain no toxic materials, making them the preferred choice, especially for use with children.
